Current status of solvents used in the pharmaceutical industry

Abstract Solvents are chemical in nature and can suspend, extract, or dissolve other substances without bringing any change in the chemistry of either the substance or the solvent. Solvents can be classified as inorganic, organic, and green solvents; they are generally grouped as oxygenated solvents, halogenated solvents, and hydrocarbon solvents. Currently, green solvents are one of the most used solvents in pharmaceutical industry. Various types of solvents used in pharmaceutical industry are: cyclopentyl methyl ether solvents, water, octanoic acid-based supramolecular solvent, n-butanol and acetone, bio-based green solvent disulfides, and eutectic solvents. Each type of solvent is characterized with various properties such as viscosity, biocompatibility, physiochemistry, extraction potential, biodegradability, renewability, hydrophobicity, polarity, conductivity, hydrophilicity, and solubilizing-stabilizing abilities. The most suitable solvents include organic solvents having good properties including volatility, acid-base properties, low boiling point, suitable density, etc. Solvents play many roles in the pharmaceutical industry including as excipients, bioavailability of orally administered protein active, as intermediate of pharmaceutical solvents, semiempirical models mediated solubility, and antisolvent crystallization technique in the pharmaceutics. According to recent trends, it is cautioned that solvents other than green solvents are a major source of pollution and such solvents should be avoided in pharmaceutical industry.